Stephen Stills also played bass on Joni Mitchell's Night in the City.
He sounds like he's having a real good time playing rollicking bass stuff on the studio version, on her '68 album Song To A Seagull, produced by David Crosby.
Here's what it sounded like played solo LIVE in '67 without bass or vocal overdubs:
Now go get her debut album if you don't have it so you can hear Stills on bass!